Refrigeration



' Patented Dec. 6, 1927.

. UNITED STATES 1,651,513 PATENT OFFICE.

B. OOOKE, OI PLAINFIELD, NEW JERSEY, ASSIGNOR TO THE M. W. KELLOGG COMPANY, A CORPORATION 03 DELAWARE.-

REFRIGERATION.

Application filed April 10, 1926. Serial m. 101,145.

This invention relates to improvements in refrigeration systems, particu arly those of the type wherein the refrigerant gas used such as ammonia is separated from the re- 6 frigerant solvent, preferably water,- by distillation, condensed into l quid, form, led into an inert gas in an expansion or refrigeration chamber, reabsorbed in the solvent in H uid form and passed once more to the dis- 10 til ation a paratus for recycling. Due to ,the law 0 vapor pressures it is inevitable that some of the solvent be carried over either by distillation or mechanical entrainmeiitgto the condensation and refrigeration ll portions of the apparatus.

' A great difliculty in systems of this dev scription has been to render such a system capable of continuous operation without interruption due to the presence of the solvent contained: in the'gas being expanded.

M invention contemplates adding a distilla le refrigerant solvent freezing temperaturelowering reagent with the solvent, preferably one having a lower boiling point 26 than that of the solvent so that owing to the law of va or'pressures asufiicient amount of the distil able refrigerant solvent freezing temperature lowering reagentwill be carried over with whatever solvent is carried over 30 into the refrigeration chamber and condensed therein to liquid form to prevent said then liquid refrigerant solvent from freezing during the refrigeration caused by the expansion of the refrigerant, and returned with the distilled solvent and the refrigerant later reabsorbed therein to the still for recycling. An object of my invention therefore is to make a refrigerating machine of this type incapable of freezin during the expansion-of the refrigerant by the introduction into the circulating refrigerant and refrigerant solvent of a distillable liquid substance which will lower the freezing point of the solvent to such an extent that the solvent will not freeze under the conditions of temperature and pressure. at which the expansion of the gas takes place.

In refrigerating'apparatus of the absorption type{, it has heretofore been proposed to'use ammonia as the expansible gas, said ammonia being absorbe in water from which it is evaporated and condensed into liquid form, then introduced to the expansion chamber where it is mixed with a suitable gas such as hydrogen and. allowed to exthe liquid in the still.

absorbed by the water and returnedto the generator for further circulation. However,

in this type of apparatus the presencev of water vapors in the liquefied ammonia issuing from the condenser causes the apparatus to become inoperative unless special means are provided for preventing the clogging of the passages by the particles of frozen water which accumulate because of the reduced temperature in the expansion chamber. v According to this invention it has been found that the addition of substances which lower the freezing point of the solvent in which the refrigerant is absorbed will prevent the formation of particles of the frozen solvent, such as water, and will overcome a tendency to clog the apparatus, as pointed out. One example of a refrigerant solvent temperature lowering reagent to be added to the gas carrying solvent preferably in the generator of the refrigerating device and which has been found to be especially efficacious is ethyl alcohol. This may be added to the sol vent in any part of the system, preferably in the generator, preferably in an amount comprising from 2- to 10% of the aqueous ammonia contained therein. Owing to the effect of the rewpective vapor pressures of all}- monia, water and alcoholfthis proportion of alcohol added to the solution will producea vapor primarily of ammonia, mixed with a small amount of vapor consisting of approximately 50% water and 50% alcohol. Although a relatively small portion of alcohol beadded it is well known thata larger amount of the lower boiling constituent will exist in the vapor, be condensed and passed to the expansion chamber than existed in Obviously other alcohols ma be used and other substances such as g ycerine may be employed. Although glycerine has a higher boiling point than that of water steam distillation is a common method of purifying glycerine and although it has a much higher boiling point than water suflicient will be'carried over to prevent freezing of the water during the expansion step. Poly-hydric alcohols, such as dihydric ethylene glycol may be employed in place of monohydric alcohols, such as ethyl alcohol or methyl alcohol with satisl'actory results. all of which are soluble in water. its is well known there is a large variety ol' other liquids which will emit vapors or be mechanically entrained in the presence ot water even it the temperature is not raised above that ol boiling water.

()no instance ol' the utilization of this in vention is illustrated in the accompanying drawing forming a part of this specification, in which the figure shown a schematic diagram of the various element of the apparatus and their pipe connections. In this drawing the illlllitl'll 1 indie: es a combination boiler or generator. This is heated in any prel'erable way, uch as by the electrical heating element 1! having leads connected with a uitablc source ot electricity, such the usual house lighting mains. As indi cated in the ligurcthis heating element has a portion t extending into the boiler and a portion i) outside the boiler. the purpose of which will be relerrcd to hereafter. From the t p ol the boiler or generator 1 a pipe (3 extends through a condenser T. which is furnished with cording water or other col Eng medium through the pipe s and from which condenser the cooling medium s discharged by the pipe 9. The pipe 6 connects with the uppe" portion of an evaporator to wh ch is pret't-rably provided with internal ballle-- ll. The numeral l1! indicates a dis charge pipe l'rom the evalmrator 10 which passes into the lower portion of an absorber 13. Th s absorber is provided with a jacket lat for containing a suitable cooling medium. such as water. and is prelerablv connected with the condenser T through the pipe 2) as indicated. The jaclv'et ll l provided with a disrha: pipe II. The top at the absorber 1; is tti'tlllttltfi'l with the evaporator ll) b v mean at a pipe in. A pipe lT extends from the bottom of the absorber ll 'hrougit a chamber 18. which acts as a heat interchanger to supply heat trom the lluid contained therein to the pipe l? which is continucd as indicated at ll) and wound helirally about the heating element 5), from which it Ptlitlr into the upper portion of the gene ator 1 above the level oi the liquid therein. as indicated at 20. The heat inten changing chamber l8 is connected with the lower portion ol the generator 1 by a pipe 521 and with the upper portion of the absorber 3 by a pipe 22. The absorber 13 is preferllil) provided with hatllcs as indi "ated at 23. lhe generator l is partially tilled with aqueous ammonia containing :2 to to per cent of alcohol or sim lar substance as above mentioned. up to about the level indicated and the absorber ll and the remaining space abtne said lewl in the system is tilled with hydrogen or other suitable gas suelras helium. and tllllllit rtlll under a pressure of several atmo-pheres. Water or other suitable cooling medium passes through the pipe 8 into the condenser 7 through the )ipe 9 into the jacket ll and is discharged t irough the pipe 15. The operation of this term of apparatus may be described as follows: Heat being prtiiduced by the heating element 4 within the generator 1 the aqueous ammonia. and alcohol is heated to such a point that the ammonia is driven oil through the pipe (3, toget her with a slight amount of water vapor containing alcohol in solution .as above pointed out. The ammon'n and Water a por passes'through the ondenser 7 where the ammonia, wateand alcohol vapors are liquclicd and drop into the evaporator 1t). Assuming the pressure in the generator 1 and in the absorber 13 to be about 150 pounds. the total ell'ective pressure in the evaporator will also be 150 pounds, but this pressure will be composed of two independent vapor pressures of say 40 pounds and M0 pounds, that is to say, the pressure. at the ammonia gas will be 40 pounds and the pressure of the hydrogen gas will be ill) pounds. Thus the ammonia will immediatel v expand and absorb the heat from the space surrt'iunding the chamber 10, thereby producing retrigeration.

Owing to the fact that the water vapor contained in the ammonia introduced at the top of the evaporator 10 has been provided with alcohol or a similar substance for reducing the freezing point, the water vapor contained in the ammonia will not freeze and will be discharged to the bottom of the chamber ll) in liquid form. thereby keeping the svstem at all times free trom obstruction or interruption. The mixture of ammonia gas, hydrogen and nater vapor will be discharged from the evaporator 10 through the pipe 1'2 into the absorber 13. It is here met by a spray of \\'ttl(1',00l1- tainlng ammonia to a slight amount, which is supplied through the pipe from the generator 1 through the heat interchanger l8. This water which [lows by gravity from the generator to the absorber readily absorbs the major portion of the ammonia gas previously introduced therein and also the entrained alcohol and water. The inert gas or hydrogen is thus stripped of the ammonia. and thereafter assumes the total pressure in the upper part of the absorber which has been indicated as lot) pounds there or less according to the pre lerred pressure employed. The released light hydrogen gas rises by vir tue of its lighter weight and thereaf er is discharged through the pipe 16 into the evaporator where it is again mixed with ammonia gas and discharged through the pipe 12, tints completing its cycle in the appart tus. The dischargeot' the strong absorption liquid or aqueous ammonia from the bottom of the absorber 13 into the generator 1 is taeilitatied by the use of the thermosiphoa principle which may he applied as indicated by using a helical coil 19 as a part of the pipe 17 about the heater 5. The strong aqueous ammonia is then dischar ed into the generator 1 through the end 20 0 the supply pipe, thus completing the cycle of the clrcu- 'lating and refrigerating medium in the system;

From the above description it will be apparent that difliculties in the use of circulating mediums in various proctsses where have described ammonia as the solvent and alcohol as'the refrigerant solvent temperature lowering reagent it is obvious that other equivalent materials may be substituted therefor. In the claims I employ the words carried over or d stilled to include either actually distilled or mechanically entrained with a distilled vapor.

Having thus described this form of the invention, what is claimed and desired to protect by Letters Patent is as follows:

l. The herein described improved step of preventing freezing of a distillable liquid refrigerant solvent in the refrigeration ste ofa distillation refrigeration process whicii comprises adding a distillable refrigerant solvent freezing temperature lowering reagent havinga lower boiling point than that of the solvent to the refrigerantsolvent whereby enough of said refrigerant solvent f eezing temperature lowering reagent may be carried over with -whatever solvent is carried over to the refrigeration chamber and condensed therewith to liquid form to prevent said then liquid refrigerant solvent from freezing during the refrigeration caused by the expansion of the refrigerant and returned with the distilled solvent and the refrigerant later reabsorbed therein to the still for recycling.

2. The. herein described improved step of preventing freezing of a. distillable liquid refrigerant solvent in the refrigeration step of a distillation refrigeration process which comprises adding a distillable refrigerant solvent freezing temperature lowering reagent to the refrigerant and refrigerant solvent whereby enough of said refrigerant solvent freezing temperature lowering reagent may be carried over With whatever solvent is carried over to the refrigeration chamber and condensed therewith to liquid form to prevent said then liquid refrigerant solvent from freezing during the refrigeration caused by the expansion of the refrigerant and returned with the distilled solvent and the refrigerant later reabsorbed therein to the still for recycling.

3. The herein described improved step in a distillation refrigeration process which comprises adding and cycling a suiiicient quantity of a distillable refrigerant solventfreezing. temperature lowering reagent with the refrigerant and whatever solvent maybe carried over through the distillatiomcondensation, refrigeration and absorption steps thereof to prevent freezing of the then liquid refrigerant solvent during the refrigeration step.

4. The herein described improved step for preventing freezing of water in the refrigeration ste of a distillation refrigeration process which comprises adding alcohol to the ammonia and water whereby enough of said alcohol may be carried over with whatever water is carried over to the refrigeration chamber and condensed therewith in liquid form to prevent said then liquid water from freezing during the refrigeration caused by the expansion of the ammonia and returned with the distilled water and the ammonia later reabsorbed therein to the' absorption steps thereof toprevent freezing of the: said then liquid water during the refrigeration step.

MAURICE B. COOKE. 

